Electric gas lamp



July 10, 1923 1,461,360

A. LEDE'RER ELECTRIC GAS LAMP 4 Original Filed July 18, 1914 INVENTOR ANTON LEDERER Patented July 10, 1923.

UNITED STATES PATENT OFFIQE.

ANTON LEDERER, OF VIENNA, AUSTRIA. ASSIGNOR TO WESTINGHOUSE LAMP COM- PANY, A CORPORATION OF PENNSYLVANIA.

ELECTRIC GAS LAMP.

Application filed July 18, 1914, Serial No. 851,836. Renewed May 3, 1921. Serial T 0 all whom it may concerns Be it known that I, ANTON Lnonnnn, a subject of the Emperor of Austria, and a resident of Vienna, Austria, have invented certain new and useful Improvements in Electric Gas Lamps, of which the following is a specification.

This invention relates to electric gas lamps, that is to say electric lamps in which a gas or mixture of gases, particularly the so called rare gases such as neon, helium, argon, krypton, etc., forms the light giving medium.

In order to reduce the amount of the potential drop required to operate electric gas lamps of this kind it has already been proposed to form the electrodes of the alkali metals or their alloys. Electrodes consisting of an alkali metal however have great disadvantages chiefly arising from the fact that the alkali metals are very easily oxidized and also burn very easily, which renders it very difficult to introduce electrodes of these metals into the lamp and at the same time preserve their bright surface. A fur ther disadvantage is that the oxides of these metals attack the glass parts of the lamp. Alloys of the alkali metals, for instance certain alloys of sodium and potassium, are liquid, which fact involves thedisadvantage that the lamps have to be handled with the utmost care in order to retain the electrodes in the vessels destined for that purpose. Also, the solid alkali metal electrodes re quire special receptacles attached to, the lighting tube and such receptacles must be provided with some kind-of partition or guard, such for instance as a piece of wire gauze to prevent the contents of the receptacles from escaping therefrom, It follows that electrodes of the alkali metals pr their alloys endanger the certainty of operation of the lamp and also render-the construction of the lamp complicated, so that the advantages which these electrodesofi'er are almost negatived by the disadvantages.

According to the present invention electric gas lamps may be operated with the same low potential drop as is possible by the use of alkali metal electrodes, with the further advantage that the electrode material may be of any one of a large number of suitable light or heavy metals such for instance as-aluminium, magnesium, tungsten, or the like. In order to enable lamps having such electrodes to be operated with a small potential drop the'lighting tubes contains small quantities of one or more of the alkali metals in a liquid or solid state, preferably in the form of a deposit. In most cases mere traces of these metals or alloys are sufiicient. Such lamps will operate with certainty and are extremely simple in their construction and manufacture. i

The alkali metal or metals may for example be introduced in a gaseous form in the following manner: A small quantity of an alkali metal or of an alloy of such metals is placed in a small addition or pocket attached to the lighting tube of the lamp. By suitable heating the metal or alloy is caused to vaporize and as soon as the vapour has entered the lighting tube so that it can deposit on the inner'wall of the tube, the above mentioned addition or pocket is sealed ofi' and the lamp finished in the usual manner.

The lighting tube of the lamp as such is preferably left free of any traces of the alkali metal or metals, which latter are preferably restricted to the vicinity of the electrodes. It is even sufficient to restrict the presence of the alkali metal or metals to the region of the anode alone. In this case the presence. of the alkali metal .or metals is preferably manifested in the form of a deposit of the metal or metals on the inner Wall of the lamp tube in the region of the anode. In this way that part of the, lighting tube which forms the real source of light may be left free of any deposit or invention may be had by reference to the accompanying drawing which illustrates diagramatically'a conventional type of electric gas lamp having temporarily connected thereto a vessel from which the alkali metal or metals may be vaporized to form a deposit within the lamp.

More particularly, the drawing illustrates a glass envelope 4: of a shape'havmg enlarged cylindrical end portions 5 and 6 connected by a light-giving tube portion 7, the tube being filled with a rare gas or a mixture of rare gases. The electrodes 9 and 10 may be sealed into the cylindrical portions 5 and 6 by means of leading-in conductors 12 and 13 respectively.

To the lower end of the tube 5 a receptacle 15 is sealed and opens thereinto and contains a quantity of an alkali metal, such, for example, as sodium. At the upper end of the cylindrical portion 6 is an exhaust tube 16 shown as sealed, which operation is performed after the tube has been exhausted in any approved manner.

After the exhaustion of the envelope 4 and either before or after the introduction of the gaseous atmosphere, the alkali metal contained in the receptacle 15 may be vaporized by heating the latter, as with a Bunsen flame. The metal vapor thus enters the envelope of the lamp and is deposited within the same, particularly in the vicinity of the electrodes 9 and 10 and obviously on the electrodes themselves, as well as on the inner wall of the glass envelope. The amount of metal vaporized need be very small, and preferably is restricted to a. thin metallic deposit which will only very slightly impair the radiation of light emitted from the light-giving portion 7 of the envelope 4. After the introduction of the alkali metal within the lamp the pocket 15 may be sealed off as at 17 While I do notdesire to be restricted to any theory of'operation of a lamp made according to my invention it appears that the presence of a slight amount of alkali metal on the electrodes diminishes the starting voltage of the lamp and this deposit is especially valuable when the lamp is filled with a rare gas. particularly neon, as by employing these features and having proper regard for constructional details a lamp may be produced which will start on 110 volts, A. G. or D. C.

The true function of the alkali metal,

however, may be other than that mentioned but it is to be understood that the essential feature of the invention is the presence of a relatively small quantity of one or more of the alkali metals deposited within the lamp.

It should also be understood that a method has been provided whereby one of these metals may be introduced into a lamp so that a beneficial action is exerted thereon, particularly with respect to lowering its starting voltage.

In the appended claims the term alkali metals is employed in specifying the formation of a thin deposit within the lamp, but I wish it to be understood that in using this term I contemplate the alloys of such metals.

I claim as my invention:

1. An electric gas lamp comprising an envelope enclosing a gaseous atmosphere, non-alkali metal electrodes and a relatively small quantity of an alkali metal in the form of a deposit.

2. An electric gas lamp comprising an envelope enclosing neon, non-alkali metal electrodes and a relatively small quantity of an alkali metal in the form of a deposit.

3. An electric gas lamp comprising an envelope enclosing a rare gas, non-alkali metal electrodes and a relatively small quantity of an alkali metal in the form of a deposit.

4. An electric gas lamp comprising an envelope enclosing a gas, non-alkali metal electrodes nd a relatively small quantity of an alkali metal aflixed to at least one of said electrodes.

5. An electric gas lamp comprising an envelope enclosing a mixture of gases, nonalkali metal electrodes and a relatively small' quantity of an alkali metal on at least one of said electrodes.

6. An electric gas lamp comp-rising an envelope enclosing a mixture of rare gases, non-alkali metal electrodes and a relatively small quantity of an alkali metal on at least one of said electrodes.

7. An electric gas lamp comprising an envelope enclosing neon, non-alkali metal electrodes and a relatively small quantity of an alkali metal on at least one of said electrodes.

8. An electric gas lamp comprising an envelope enclosing neon, aluminumelectrodes and a thin layer of an alkali metal deposited on said electrodes.

9. An electric gas lamp comprising an envelope enclosing neon, non-alkali metal electrodes having deposited as a coating thereon a relatively small quantity of an alkali metal.

10. An electric gas lamp comprising an envelope enclosing neon, non-alkali metal electrodes having a relatively thin coating thereon consisting of a small quantity of an alkali metal.

11. An electric gas lamp comprising an envelope enclosing-a gas, non-alkali metal electrodes and a relatively small quantity of an alkali metal combined with at least one of said electrodes.

12. An electric gas lamp comprising an envelope enclosing neon and electrodes within said envelope, at least one of said electrodes comprising a non-alkali metal and a small quantity of an alkali metal.

13. An electric gas lamp comprising an envelope enclosing a rare gas, non-alkali metal electrodes and a relatively small quan- {ity of an alkali metal within said envealkgli metal on at least one of said elec 5 ope. tro es.

14. In an electric discharge device, an 17, The method of lowering the potential electrode comprising a non-alkali metal havdrop in an electric gas lamp. having noning combined therewith a. small quantity of alkali metal electrodes, which comprises dean alkali met'al. positing 'a relatively small. quantity of an 20 15. In an electric discharge device, an alkali'metalin theinterior of the lamp. electrode comprising a non-alkali metal hav- In testimony whereof I have hereunto.-

ing a coating of an alkali metal formed subscribed my name this 9th day of July,

' drop in an electric gas lamp provided with l Witnesses:

thereon. v 1914. v

16. The method of lowering the potential ANTON LEDERER;

nonalkali metaL electrodes which comprises 7 AUGUST Foam, I depositing a relatively small quantity of am ADA MARIE Bnmn. 

